http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12940 Of key importance in convex analysis and optimization is the notion of duality, and in particular that of Fenchel duality. This work explores improvements to existing algorithms for the symbolic calculation of subdifferentials and Fenchel conjugates of convex functions defined on the real line. More importantly, these algorithms are extended to enable the symbolic calculation of Fenchel conjugates on a class of real-valued functions defined on Rⁿ. These algorithms are realized in the form of the Maple package SCAT. 2013-05-22T04:02:00.930Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7550 The field of statistics has long been noted for techniques to detect patterns and regularities in numerical data. In this article, we explore connections between statistics and the emerging field of ‘experimental mathematics’. These include both applications of experimental mathematics in statistics as well as statistical methods applied to computational mathematics. 2013-05-21T01:27:03.416Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7551 Review of: The Princeton Companion to Mathematics. Edited by Timothy owers, with June Barrow-Green and Imre Leader. Princeton University Press, Princeton, NJ, 2008. $99.00. xxii+ 1034 pp., hardcover. ISBN 978-0-691-11880-2. 2013-05-16T05:23:43.804Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7552 Herein we develop connections between zeta functions and some recent "mysterious" constants of nonlinear physics. In an important analysis of coupled Winfree oscillators, Quinn, Rand, and Strogatz [Quinn et al. 07] developed a certain N-oscillator scenario whose bifurcation phase offset small ⍉ is implicitly defined, with a conjectured asymptotic behavior sin ⍉ ~ 1−ᴄ₁/N, with experimental estimate ᴄ₁ = 0.605443657 . . .. We are able to derive the exact theoretical value of this "QRS constant" ᴄ₁ as a real zero of a particular Hurwitz zeta function. This discovery enables, for example, the rapid resolution of c1 to extreme precision. Results and conjectures are provided in regard to higher-order terms of the sin ⍉ asymptotic, and to yet more physics constants emerging from the original QRS work. 2013-05-16T05:01:40.840Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7257 Measures of diet quality have evolved with a number of scoring indices currently in use. They are increasingly being used to examine epidemiological associations between dietary intake and nutrition-related health outcomes. The present review aims to describe current diet quality tools and their applications, and to examine the relationship between diet quality and morbidity and mortality. A search was conducted of MEDLINE, Cochrane, EMBASE, CINAHL and ProQuest electronic databases. Inclusion criteria were: English language; published from 2004 on; conducted in adult populations; longitudinal/cohort/case–control or cross-sectional study; included a theoretically defined measure of diet quality. A total of twenty-five indices of overall diet quality and/or variety were found, with components ranging from nutrients only to adherence to recommended food group servings, to variety within healthful food groups. The majority of studies reviewed had methodological weaknesses but demonstrated that higher dietary quality was consistently inversely related to all-cause mortality, with a protective effect of moderate magnitude. The associations were stronger for men and for all-cause and CVD mortality. The limitations of both the indices and the studies that use them need to be considered when interpreting and comparing results. However, diet quality indices do appear to be able to quantify risk of some health outcomes, including biomarkers of disease and risk of CVD, some cancers and mortality. Further research is needed to improve the validity of these tools and to adapt them for use in clinical dietetic practice. 2013-05-13T04:18:38.821Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7737 Dietary intake during childhood and adolescence is of increasing interest due to its influence on adult health, particularly obesity, cardiovascular disease and diabetes. There is a need to develop and validate dietary assessment methods suitable for large epidemiologic studies of children and adolescents. Limited large scale dietary studies of youth have been undertaken in Australia, due partly to the lack of a suitable dietary intake tool. A self-administered, semi-quantitative food-frequency questionnaire (FFQ), the 'Australian Child and Adolescent Eating Survey' (ACAES), was developed for youth aged 9-16 years. This study evaluated reproducibility and comparative validity of the ACAES FFQ using assisted food records (FRs) as the reference method. The ACAES FFQ was completed twice (FFQ1 and FFQ2) at an interval of 5 months, along with four one-day assisted FRs. Validity was evaluated by comparing the average of the FRs with FFQ2 (n = 113) as well as with the average of FFQ1 and FFQ2 (n = 101). Reproducibility was evaluated by comparing FFQ1 and FFQ2 (n = 101). The two methods were compared using correlations, Kappa statistics and Bland-Altman plots. Correlation coefficients for comparative validity ranged from 0.03 for retinol to 0.56 for magnesium for transformed, energy-adjusted, deattenuated nutrient data, with correlation coefficients greater than 0.40 for total fat, saturated fat, monounsaturated fat, carbohydrate, sugars, riboflavin, vitamin C, folate, beta-carotene, magnesium, calcium and iron. Correlation coefficients for reproducibility ranged from 0.18 for vitamin A to 0.50 for calcium for transformed, energy-adjusted, deattenuated nutrient data. The ACAES FFQ ranked individuals reasonably accurately, with the comparative validity analysis showing that over 50% of participants were classified within one quintile for all nutrients, with only a small percentage grossly misclassified (0-7%). The ACAES FFQ is the first child and adolescent specific FFQ available for ranking the dietary intakes of Australian children and adolescents for a range of nutrients in epidemiologic research and public health interventions. 2013-05-13T04:16:32.266Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7154 Correlation is often used to assess both independence and linearity in two dimensions, but is not well understood in higher dimensions. Here we take a closer look at these uses of correlation in two dimensions and how these assessments might be extended to higher dimensions. Our discussion will focus on the simple case of understanding the nature of correlation for association models for two- and three-way contingency tables, but can also be considered in a more general setting. 2013-05-09T01:02:39.324Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7914 For at least partially ordered three-way tables, it is well known how to arithmetically decompose Pearson's X²p statistic into informative components that enable a close scrutiny of the data. Similarly well-known are smooth models for two-way tables from which score tests for homogeneity and independence can be derived. From these models, both the components of Pearson's X²p and information about their distributions can be derived. Two advantages of specifying models are first that the score tests have weak optimality properties and second that identifying the appropriate model from within a class of possible models gives insights about the data. Here, smooth models for higher-order tables are given explicitly, as are the partitions of Pearson's X²p into components. The asymptotic distributions of statistics related to the components are also addressed. 2013-05-08T23:20:41.527Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9109 Corporatisation seeks to transform the performance of government trading entities; a transformation which often relies on changing how work is performed and how management and labour interact. Hunter Water - as it is now known - was the first water utility in Australia to undergo corporatisation. Against the broader corporatisation literature, this paper reviews how, from the 1980s, Hunter Water’s operations were initially restructured around a commercialisation imperative and, then corporatised in 1992. The responses of the unions, including (shelved) privatisation plans are outlined. The case study highlights that more research is needed to record and analyse changes in employment relations which followed the utility’s corporatisation, especially, in terms of employment regulation, management strategy, the structure and coverage of unions and organisational performance. 2013-05-01T01:56:48.953Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8097 This paper provides a brief overview of the development of business incubation across Australia. The first incubators appeared in the country in the early 1980s, funded by state and territory governments. This was shortly followed by an extensive program of support from the federal government, which led to a rapid expansion from 49 incubators in 1996 to almost one hundred in 2005. Australian incubation has a number of distinctive characteristics. Most have usually been initiated and subsequently managed by a local municipality, regional economic development organisation or business group, with support from government. Almost all incubators operate as not-for-profit ventures. Government assistance is usually directed towards the establishment of centres, rather than supporting their on-going operations. The most common form are either stand-alone models, or else ones embedded with other small business support centres; technology-based incubators represent a much smaller proportion of the overall incubator population, and there is a relatively low level of involvement by universities and the research sector. Australian incubators are, in the main, focused on providing support to the general small business community and nascent entrepreneurs, rather than on commercialising technology from research bodies. The emphasis has therefore been on providing affordable, flexible office space for tenants; access to shared resources; business advice and help; and links to professional and commercial networks, rather than commercialisation through technology transfer and capital inflows. 2013-05-01T00:39:37.877Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12827 Finding a delivery plan for cancer radiation treatment using multileaf collimators operating in “step-and-shoot” mode can be formulated mathematically as a problem of decomposing an integer matrix into a weighted sum of binary matrices having the consecutive-ones property and sometimes other properties related to the collimator technology. The efficiency of the delivery plan is measured by both the sum of the weights in the decomposition, known as the total beam-on time, and the number of different binary matrices appearing in it, referred to as the cardinality, the latter being closely related to the setup time of the treatment. In practice, the total beam-on time is usually restricted to its minimum possible value (which is easy to find), and a decomposition that minimizes cardinality (subject to this restriction) is sought. This decomposition problem is known to be NP-hard, and the best available exact solution methods cannot solve, in reasonable time, problems with dimensions large enough to be of use in actual medical applications. In this paper, we propose a new heuristic. To ensure that the heuristic is computationally efficient, we make use of exact bounds that apply to the decomposition and prove that these bounds can be computed efficiently. We demonstrate that the heuristic performs very well numerically against the best previously published heuristic (that of Kalinowski), reducing the average gap between the cardinality of the solution found and the optimal value by 37% on the largest problems tested (for which optimal solutions could be found). Importantly, this new heuristic performs well on those instances that are problematical for Kalinowski's heuristic. A “best-of” algorithm, combining heuristics, produces a decomposition with cardinality within one of optimal in about 98.7% of instances tested (for which an optimal solution is available). It reduces the cardinality of solutions produced by about 5% on average. On instances for which optimal solutions can be found, it more than halves the optimality gap and finds an optimal solution in about 28% more cases than Kalinowski's heuristic. 2013-04-30T06:44:59.493Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12787 In many path-planning situations we would like to find a path of constrained Euclidean length in R2 that minimizes a line integral. We call this the Continuous Length-Constrained Minimum Cost Path Problem (C-LCMCPP). Generally, this will be a nonconvex optimization problem, for which continuous approaches ensure only locally optimal solutions. However, network discretizations yield weight constrained network shortest path problems (WCSPPs), which can in practice be solved to global optimality, even for large networks; we can readily find a globally optimal solution to an approximation of the C-LCMCPP. Solutions to these WCSPPs yield feasible solutions and hence upper bounds. We show how networks can be constructed, and a WCSPP in these networks formulated, so that the solutions provide lower bounds on the global optimum of the continuous problem. We give a general convergence scheme for our network discretizations and use it to prove that both the upper and lower bounds so generated converge to the global optimum of the C-LCMCPP, as the network discretization is refined. Our approach provides a computable lower bound formula (of course, the upper bounds are readily computable). We give computational results showing the lower bound formula in practice, and compare the effectiveness of our network construction technique with that of standard grid-based approaches in generating good quality solutions. We find that for the same computational effort, we are able to find better quality solutions, particularly when the length constraint is tighter. 2013-04-26T01:31:11.239Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12793 Given a discretisation of an orebody as a block model, the open pit mining production scheduling problem (OPMPSP) consists of finding the sequence in which the blocks should be removed from the pit, over the lifetime of the mine, such that the net present value (NPV) of the operation is maximised. In practice, due to the large number of blocks and precedence constraints linking them, blocks are typically aggregated to form larger scheduling units. We aim to solve the OPMPSP, formulated as a mixed integer programme (MIP), so that aggregates are used to schedule the mining process, while individual blocks are used for processing decisions. We propose an iterative disaggregation method that refines the aggregates (with respect to processing) up to the point where the refined aggregates defined for processing produce the same optimal solution for the linear programming (LP) relaxation of the MIP as the optimal solution of the LP relaxation with individual block processing. We propose several strategies of creating refined aggregates for the MIP processing, using duality results and exploiting the problem structure. These refined aggregates allow the solution of very large problems in reasonable time with very high solution quality in terms of NPV. 2013-04-19T04:41:36.142Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12792 The effectiveness of radiation therapy for cancer depends on the patient remaining still during treatment. It is thus important to minimize the total treatment time (TTT). When such treatment is delivered using multileaf collimators in “step-and-shoot” mode, it consists of a sequence of collimator configurations, or patterns; for each, the patient is exposed to radiation for a specified time, or beam-on time. The TTT can thus be divided into the total beam-on time and the time spent reconfiguring the collimators. The latter can reasonably be approximated by the number of patterns, multiplied by a constant overhead time per pattern. Previous approaches to this problem have all been heuristic; in particular none of them actually use the pattern overhead time to ascertain the best trade-off between beam-on time and number of patterns. In this paper, we develop exact solution approaches, based on mixed integer programming (MIP) formulations, which minimize the TTT. We consider direct solution of MIP formulations, and then exploit the bicriteria structure of the objective to derive an algorithm that “steps up” through the number of patterns used, leading to substantial computational savings. 2013-04-19T04:40:18.155Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8877 For most real-world problems, especially those arising in environmental decisionmaking, natural models are nonlinear. In optimization, the complexity of solving nonlinear problems can be reduced by introducing some appropriate problem-dependent simplification that transforms the nonlinear problem to a more easily solved integer linear programming problem. Such techniques are increasingly being utilized in the modelling and solution of environmental problems, not least because the resulting formulations can often be solved in practice: progress in linear and integer programming solvers and software tools over the last ten years or so has meant more reliable and rapid solution of even large-scale problems. This talk will describe two cases of environmental problems tackled with integer progamming, highlighting its modelling power. The first case concerns river systems, and decisions about environmental flows, addressing questions such as how much to release, and when. The second case concerns forestry. Harvest scheduling in forestry has for some time been planned with the aid of integer programming tools; now environmental considerations, such as habitat preservation, are being incorporated in such models. Solution approaches used, and future challenges, will also be discussed. 2013-04-19T00:38:15.634Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8706 Synchronous machines are commonly modelled using d- and q-axis equivalent circuits. Here, we present an approach to the ensuing parameter estimation problem which employs the technique of indirect inference. In indirect inference, an intermediary model is employed which is computed for both the true system and the preferred model, in this case the equivalent circuit model. We have used frequency response data from standard standstill machine tests as the intermediary model. The circuit parameters of the model are optimised, such that the measured difference between the standstill frequency responses of the equivalent circuit model and the true system are minimised. 2013-04-19T00:14:41.919Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8750 Given the current financial crisis, there is renewed interest in modelling how the price of commodities change in the market. Traditionally, such models have assumed constant parameters. However, large and sudden changes in the parameters can also be anticipated due to market shocks. This paper is aimed at addressing this issue. We first describe a bias-variance trade-off in parameter estimation when sudden changes are considered. We then propose a mechanism to achieve a compromise between the observed bias and variance. A key ingredient of this mechanism is to use an estimator having a variable memory length. 2013-04-19T00:12:47.970Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6981 This paper considers the profile of research administration, based on a survey of 36 Australian universities. The findings identify a group that is typically female, older and university qualified. Males tend to be more likely than females to have a research higher degree, earn a significantly higher salary and move up the salary scale at a faster rate. Of the 194 respondents more than half reported previous research experience with just under one third having previously been employed as an academic. Almost two thirds had worked in research services for five or fewer years and the majority reported they had held their current position for five or fewer years. 2013-04-15T07:35:28.899Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8888 For more than a decade the unique challenges facing Visual Arts researchers have been the subject of debate. Creative practice-based research challenges conventional and presumed ways to legitimately construct knowledge and the clash in paradigms is pronounced in deliberations on funding; research quality; and research degrees. As the language of creativity collides with that of established scientific discourse, research students have been the forefront and it is through the growth in these degrees that the position of creative research is being advanced. Students are faced with the complex demands of candidature while also negotiating the shifting sands of a new and evolving research discourse. 2013-04-15T07:32:50.122Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9058 Many reinforced concrete (RC) structures are deteriorating due to chloride and/or carbonation induced corrosion. A spatial time-dependent structural reliability model is developed that calculates (i) strength degradation with time, (ii) probability and extent of corrosion damage (cover cracking) and (iii) probability of collapse for RC structures subject to pitting corrosion. This enables accurate service life predictions to be made. These models include the spatial and temporal variability of cover, concrete strength, chloride exposure, corrosion rate, corrosion initiation, cover cracking, pit depth, etc., as well as the time-dependent variability of loadings. The effect of maintenance strategies, such as periodic inspections, on updated reliability and service life predictions are also estimated. Illustrative examples are given for RC beams whose performance and reliability are updated using visual inspection findings of corrosion damage. Information about service life prediction, and updating based on (new) condition assessment findings, is essential for asset management of deteriorating structures. 2013-04-15T06:55:51.486Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7751 This paper presents the feasibility of applying an ultra-wideband (UWB) wireless scheme to both high data rate implantable neural recording and low data rate wearable biomedical applications. An extensive analysis on the UWB signal generation for biomedical application is discussed. A CMOS UWB transmitter has been designed, fabricated, and used in a high data rate neural recording system. A method to readily assemble a flexible UWB transmitter for wearable physiological monitoring system is also presented. An eight-channel low data rate recording system for monitoring multiple continuous electrocardiogram and electroencephalogram signals has been designed, and its test results are presented. 2013-04-15T05:59:18.389Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7867 In implanted biomedical devices, due to the presence of surrounding dissipative biological tissue, the antenna suffers poor impedance matching. This causes degradation in the performance of a wideband or ultra-wideband (UWB) implanted device. Moreover, the electrical properties of tissue change from organ to organ, and possibly from time to time. In this paper, it is shown that loading of antennas with suitable insulators can deliver broadband matching across a range of dissipative medium properties. An impedance-matched UWB antenna designed to operate inside a lossy medium, which has varying electromagnetic properties within the range expected in biological tissues, is presented. The operating bandwidth of the proposed design is 3.5-4.5 GHz, which is an interference-free subset of the unlicensed UWB band in the US. It is demonstrated that once the dielectric loading is applied, the conventional procedure for antenna design in free space can be followed. The proposed implantable small capsule-shaped slot antenna has been characterized using numerical simulations. Details of a proof-of-concept experiment are presented. 2013-04-15T04:17:24.040Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7722 A compact, printed, capsule-shaped ultrawideband (UWB) antenna for biomedical implants is presented. The 10-dB return loss bandwidth of the proposed antenna is 3.5-4.5 GHz, which covers the recently proposed UWB for biomedical applications. The antenna matching has been optimized using CST Microwave Studio and verified by measurements. An optimized feed mechanism to reduce guided wavelength, as well as integration with other electronics, has been considered in the antenna design. Radiation performance has been evaluated on an impulse-based UWB transmitter/receiver testbed to show that the antenna is usable in biomedical applications, such as capsule endoscopes. The antenna has been tested both in free space and with tissue loading. 2013-04-15T04:15:04.379Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7750 This paper reports a 128-channel neural recording integrated circuit (IC) with on-the-fly spike feature extraction and wireless telemetry. The chip consists of eight 16-channel front-end recording blocks, spike detection and feature extraction digital signal processor (DSP), ultra wideband (UWB) transmitter, and on-chip bias generators. Each recording channel has amplifiers with programmable gain and bandwidth to accommodate different types of biological signals. An analog-to-digital converter (ADC) shared by 16 amplifiers through time-multiplexing results in a balanced trade-off between the power consumption and chip area. A nonlinear energy operator (NEO) based spike detector is implemented for identifying spikes, which are further processed by a digital frequency-shaping filter. The computationally efficient spike detection and feature extraction algorithms attribute to an auspicious DSP implementation on-chip. UWB telemetry is designed to wirelessly transfer raw data from 128 recording channels at a data rate of 90 Mbit/s. The chip is realized in 0.35 μm complementary metal-oxide-semiconductor (CMOS) process with an area of 8.8 times 7.2 mm² and consumes 6 mW by employing a sequential turn-on architecture that selectively powers off idle analog circuit blocks. The chip has been tested for electrical specifications and verified in an ex vivo biological environment. 2013-04-15T04:14:19.448Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8768 Ultra Wideband (UWB) has many favorable factors for use in a wireless body area network application. The major drawback is the high power consumption of an UWB receiver. One solution to address this problem is to use a transmit-only UWB sensor node. In this paper, we propose a multi-access scheme that is suitable for asynchronous transmit-only UWB wireless body area networks (UWB-WBAN). Each sensor attached on the patient under monitoring is assigned a unique number of UWB pulses per data bit. The number of UWB pulses assigned to the sensors is optimized to improve the bit error rate and system reliability. Simulation shows that through careful selection of the number of pulses for the sensors, it is possible to maintain almost similar bit error probability, regardless of the distance from the receiver. 2013-04-15T02:36:05.492Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8676 This paper investigates methods to enhance the reliability of an ultra-wideband transmit-only (UWB Tx-only) sensor system. UWB Tx-only system uses asynchronous burst transmission, where each individual sensor transmits periodically without prior knowledge of other users and the channel condition. The application of UWB Tx-only sensor system for wireless body area network (WBAN) in a single user and multiple user environments is presented. In a single user environment, the main source of interference is from the collision of transmitted signals from individual sensors on the body. In a multiple user scenario, apart from the interference due to collision, there is also another source of interference from transmitting sensors of nearby users. The two major factors affecting the system reliability are the signal to noise ratio and the probability of collisions. The signal to noise ratio can be enhanced with a higher transmission power, which can be achieved through the use of gated systems and by carefully optimizing the pulse repetitive frequency and the gating duty cycle when generating an UWB transmission signal. Meanwhile the collision probability in a Tx-only UWB WBAN system can be reduced by arranging unique transmission intervals. It is shown in this paper that the collision probability for the case of burst transmission can be reduced to less than twice that of a pulse transmission through careful selection of the transmission interval. 2013-04-15T02:33:31.837Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8757 Ultra-wideband (UWB) technology has been considered for the physical layer in recently proposed IEEE 802.15 standard (TG6) for wireless body area networks. Wireless links covered by this standard will operate in UWB unlicensed band with antennas on implanted devices having small form factors. Except for those installed on-body and on external receivers, the antenna will be operating in-body, surrounded by body tissue. Body tissues have high dielectric constants and are highly dissipative. Once implanted beneath multiple layers of tissue, the device, which is expected to be consuming very low power, experience heavy losses in its transmission and reception path. Therefore, it is essential that antenna losses, both mismatch and resistive, are minimised. In this paper we will demonstrate a method to minimize antenna mismatch losses by loading the antenna with insulating material. 2013-04-15T02:31:41.428Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8587 Biomedical Implants require a clean and medically safe source of energy to perform their operations. Early implants such as pacemakers sourced their power from small lithium ion batteries. While this solution allows for the operation of the implantable device without a wire connecting the internal and external circuitry, limited battery life causes the impracticality, health risks and expense of operating on patients for the mere purpose of replacing the battery. The use of wireless power technology in implantable devices led to a more flexible range of applications which were not otherwise possible. 2013-04-15T02:29:10.730Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8763 A new type of wireless transmission coil is proposed for biomedical implants. By stacking several spirals above one another, the space required for an implantable coil is miniaturised, the self-resonant frequency (SRF) of the spiral is reduced, as is the required power transmission frequency for the implanted device. A four-layer 15 mm x 15 mm spiral coil of seven turns was simulated in CST Microwave Studio (TM), and constructed and successfully tested in hardware. 2013-04-15T02:26:52.743Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8693 This work will address the challenges to facilitate the development of a high capacity radio system for a small, miniaturized electronic pill device that can be swallowable or implantable in human body in order to detect biological signals or capture images that could eventually be used for diagnostic and therapeutic purposes. In addition to reviewing and discussing the recent attempts in electronic pill technology, a wideband (UWB) telemetry system aimed for the development of an electronic pill will be presented in this paper. We have successfully realized more than half a meter UWB link under conditions emulating an implant. 2013-04-15T02:21:56.702Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7766 In the present technical note we study the fundamental limitation on stability that arise when an additive coloured Gaussian noise (ACGN) channel is explicitly considered over either the control or measurement paths of a linear time invariant (LTI) feedback loop. By considering a linear setting we can naturally express the fundamental limitation as a lower bound on the channel signal-to-noise ratio (SNR) required for stabilisability. We start by first obtaining a closed-form expression for the squared L₂ norm of a partial fraction expansion with repeated poles in the Laplace domain. We then use the squared L₂ norm result to obtain the closed-form expression for the infimal SNR required for stabilisability. The proposed closed-form includes the case of repeated unstable plant poles and non minimum phase (NMP) zeros. 2013-04-15T02:18:03.838Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7919 The above paper obtains in closed-form the infimal signal-to-noise ratio (SNR) required for stabilization of finite-dimensional linear time invariant (LTI) feedback loops, in continuous and discrete-time, for state feedback and output feedback control. The objective of the present note is to prove that the discrete-time output feedback infimal SNR result for stabilization reported in is missing a term in delta, the component due to the relative degree of the plant model. 2013-04-15T02:15:14.926Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8732 In the present paper we obtain a closed-form solution for the class of continuous-time algebraic Riccati equations (ARE) with vanishing state weight, whenever the unstable eigenvalues are distinct. The AREs in such a class solve a minimum energy control problem. The obtained closed-form solution gives insight on issues such as loss of controllability and it might also prove comparable in terms of numerical precision over current solving algorithms. 2013-04-15T02:04:49.716Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8733 In the present paper we obtain a closed-form solution for the class of discrete-time algebraic Riccati equations (ARE) with vanishing state weighting, whenever the unstable eigenvalues are distinct. The AREs in such a class solve a minimum energy control problem for a single-input single-output (SISO) system. The obtained closed-form solution gives insight on issues such as loss of controllability and it might also prove competitive in terms of numerical precision over current solving algorithms. 2013-04-15T02:03:44.729Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9056 Om Shree Dham is a farm and also an ashram at Cedar Creek in the Hunter Valley, NSW, where ancient Vedic fire practices for purifying and healing the atmosphere are performed regularly by a group of white Australians. The main fire practice is known as Agnihotra and as well as removing the toxic conditions of the atmosphere through the agency of fire, the practice is understood to heal the practitioner. Agnihotra practitioners believe that these practices are our last chance to right the balance on earth before some final ecological cataclysm takes place. At least one member of this group joined because he felt that he was doing more thereby in the cause of environmental activism than he had been doing previously as the Newcastle organizer for Greenpeace. Viswan feels that homa therapy is also pro-active direct action like Greenpeace but of another kind. This is now his preferred form of direction action. This paper, which is based on one of the case studies for my doctorate, looks at Viswan’s explanation of these practices and at his reasoning about their efficacy and briefly looks at some implications of his thinking. 2013-04-15T02:01:20.644Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8758 Cyclic prefix (CP) based block recursive least squares (RLS) channel estimation algorithms have been proposed for orthogonal frequency division multiplexing (OFDM) systems. In this paper, we investigate the performance of CP based exponentially weighted block RLS channel estimator. Our analysis and extensive simulation results show that smaller values of exponential forgetting weightings cause increase in convergence time and steady state performance error of the algorithm. Furthermore, performance of the approach degrades with the increase in channel nulls and constellation size. 2013-04-15T01:20:26.837Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8736 Orthogonal frequency division multiplexing (OFDM) delivers high data transmission rate and forms the basis of Beyond 3G. The channel estimation is imperative for the implementation of OFDM. Cyclic Prefix (CP) based block Recursive Least Squares (RLS) channel estimation algorithm has been proposed for OFDM systems but it increases computational complexity. In this paper, we propose a block LMS (Least Mean Squares) channel estimation algorithm which promises less computation but delivers comparable and promising results. 2013-04-15T01:19:18.748Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8890 Schools are social environments and as such are concerned with the social-emotional (ie. affective) responses of students. Affective outcomes of schooling are important as they contribute positively to academic outcomes and they are equally important in and of themselves. Affective responses can be assessed quantitatively and are frequently studied as part of school and classroom environments. Within such studies students’ perceptions of school and classroom variables such as general satisfaction with school, relationships with teachers and peers, feelings of achievement and motivation and engagement are measured. These are also areas of schooling with particular relevance for boys’ education, as boys are frequently reported as less satisfied with school and less engaged and motivated in learning. Many qualitative studies have reported boys’ low levels of satisfaction with school compared to girls and subsequent lack of motivation and engagement. Yet few quantitative studies comparing boys’ and girls’ affective response to schools have been conducted. This paper will report on part of a wider study that has investigated the impact of boys’ education initiatives on boys’ and girls’ affective responses to schooling. The study collected data from nine secondary schools undertaking specific initiatives in boys’ education, the majority of which were participating in the Success for Boys program. Results from the first round of data collection (pre-intervention) has previously been reported and established that there were gender differences in perceptions of quality of school life and such differences were related to school attended. This paper will report on the second round of data collection and discuss the implications of the results. 2013-04-15T01:12:13.247Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8910 Widden Brook in the Hunter Valley, NSW, is an unregulated active sand-bed stream characterized by high flood variability. The dominant riparian tree on Widden Brook is Casuarina cunninghamiana (River Oak). Successful establishment of River Oaks require bankfull flows that gradually build bars into benches, reducing the frequency of flood scour, and sub-bankfull flows that deposit fine sediment on the benches, enhancing Oak survival and growth. Although River Oaks do not require floods to germinate, seedlings are highly susceptible to water-stress and need a subsequent moist period to establish. The rate at which the water-table falls also influences River Oak survival. Overbank flows are important for the replenishment of soil water and the alluvial aquifer. Many riparian trees use groundwater opportunistically and access during extended dry periods may be critical to their survival. River Oaks on the floodplain and the benches were most likely able to access the water-table during 2006-2008. 2013-04-10T06:56:30.120Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8737 Intense interactions between resource providers and resource consumers in collaborating and sharing their resources frequently occur in an open and dynamic Digital Ecosystem environment. Such interactions contribute to several challenges in cyber security, particularly in protecting enterprise resources from various malicious attacks. The main challenge that occurs in protecting these resources is the ability to manage multiple unique authorization permissions over the enterprise resources. Unfortunately, the inadequacies of the current security mechanisms in addressing these challenges result in a slower implementation of a potentially highly beneficial Digital Ecosystem environment. Therefore, this paper proposes a distributed mechanism for individual enterprisepsila to manage its own authorization process and resource access permissions, with the aim of providing rigorous protection of the enterprise resources in question. 2013-04-08T07:15:59.278Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7884 The newly emerging concept of Digital Ecosystem (DE) has played a significant role in today’s technology, especially for Small and Medium Enterprises (SMEs) to adopt Information and Communication Technology (ICT) inside their businesses. DE reveals the opportunities to enhance the productivity and efficiency of each business transaction. Therefore, it will further contribute to the success of the enterprise’s businesses. Along with the advancement of DE technology, security has emerged as a vital element in protecting the resources and information for the interacting DE member entities in particular. However, current developments of such security mechanisms for protecting these resources are still in their infancy. This paper proposes a distributed mechanism for individual enterprises to manage their own authorization processes and information access permissions with the aim of providing rigorous protection of enterprise resources. 2013-04-08T07:14:13.271Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9047 This paper reports on the completion of the first stage of research of a pilot study undertaken in collaboration by 3 Australian universities. The pilot involves the development of a virtual pharmacy patient (VPP) as a study of its effects on student learning when it is used as a formative assessment tool for pharmacy students in interviewing and diagnosing a patient. The design criteria that have been incorporated into the virtual patient system are described. The novelty of this system is in its ability to track and report on the style and appropriateness of student questioning of a virtual pharmacy patient. One of the main problems in this type of system is recognition of free-text student questions. An overview of the pragmatic solution to this and the systems potential as a tool to generate a lexicon for more complex question recognition is presented. 2013-04-08T07:07:39.347Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7701 Problem statement: The adoption of mobile device technology can contribute significantly to enhance customers trust in online payment systems. Approach: The perceptions and preferences of online shoppers are influenced by several key factors which serve to both enhance and compromise this trust and in turn affect a customer intentions and behavior in relation to use online payment systems. The first part of the research was a quantitative study to investigate these factors. In the second part of this research, a mobile payment model for online payment systems was proposed. In this model, the customers do not need to trust merchants during the transaction because merchants will not act as an intermediary between customers and the acquirer. Customers can therefore send their financial details without concern of disclosure, or potential misuse by the merchant. Results: In this study, the key factors influencing to adopt mobile payment systems were identify. The proposed model was developed and an analysis of the model architecture against conventional online payment systems was discussed. Conclusion/Recommendations: The significance of this research comes from providing a practical mobile payment model as a possible step towards increasing customer acceptance of online shopping and increasing their trust in online payment systems. The new model focuses on enhancing the feeling of security of the use of an online payment system and satisfying the security requirements. 2013-04-03T03:32:24.409Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8695 Flexure hinges are commonly used in many applications which require precise and smooth motions in the nanometer scale. There were various formulations derived using different methods to calculate the stiffness of circular flexure hinges. This article compares these equations with FEA predictions. The limitation of these equations at different t/R (R is the radius and t is the neck thickness) ratios are revealed. Based on the limitations of these design equations, a guideline to select the most accurate equations for hinge design calculations is presented. In addition to the review and comparisons, general empirical stiffness equations in the x- and y-direction were formulated in this study (with errors less than 3% when compared to FEA simulations) for a wide range of t/R ratios (0.05 les t/R les 0.8). 2013-03-28T01:30:31.165Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8688 This paper reports a MEMS tunable capacitor with a new actuation principle. The new design adopts electrostatic actuation of an electrically floating movable dielectric. This enables us to achieve a high Q factor by eliminating the loss associated with springs in the RF signal path. Also, the design can achieve a high tuning range, by using additional actuation combs and thus eliminating the pull-in effect. Since no DC bias is applied on the plates of variable capacitor, the parallel plates 1/3 gap limitation does not apply. The designed devices were fabricated in a SOI MEMS process, with a 25 μm thick device layer and minimum gap of 2 μm. Measurement results show that the tunable capacitor has a 135 fF initial capacitance with a tuning range of 367% and a Q factor of 56 at 1 GHz by bi-directional actuation. 2013-03-27T06:39:19.131Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8708 This paper presents the application of fuzzy clustering technique on large load data to greatly reduce calculations in reliability evaluation of restructured power systems. The method involves: first grouping a large load data into few clusters, secondly calculating partial membership value of each load point in each cluster, thirdly calculating reliability indices for each cluster and finally, expressing the reliability indices at each load point in terms of the reliability index of the cluster and the membership value that the load point has in that cluster. A non-sequential Monte Carlo simulation technique based on this framework has been proposed to evaluate the customer reliability of restructured power systems. 2013-03-27T05:43:46.022Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7687 The aim of this paper is to describe the challenges associated with conducting a pilot study designed to evaluate the effectiveness of targeting pain in older people. 2013-03-27T05:21:17.994Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8704 In many applications one needs to switch between control laws. This requires some form of bumpless transfer. Here we propose a simple bumpless mechanism for possible implementation on a set of Multi-Effect Evaporators in a Sugar Mill located in Queensland, Australia. The ultimate goal of this study is to allow on-the-fly testing of different controller designs and exchanging of control authority to achieve increased performance. 2013-03-27T01:51:46.805Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9012 “History makes us…” goes the saying but understanding what has happened over time, let alone, what might happen remain open questions. Leaving aside, for the moment, the challenges presented by the diverse faces in the Hunter Valley of industrial, mining and residential activity, which continues apace, viticulture, winegrape growing and the complex of farming/agrarian ventures present especial niche opportunities. Understanding the development of the production, distribution and consumption of speciality produce, namely, the histories of wine and food, could well shed useful light upon the past and assist in illuminating future potential. History, socio-geography and economy all play key roles in shaping the Hunter Valley’s high quality, mostly small to medium scale winemaking and viticulture enterprise. The excellence of these ventures is arguably the key to the future of the wine industry in the Hunter. Moreover, excellence and a spirit of hard-working enterprise, albeit with many a turn and tumble, stretch back to James Busby’s seminal, late Georgian optimism and venturous practical spirit embedded in the title of his agricultural report: “Journal of a recent visit to the principal vineyards of Spain and France:…with observations relative to the introduction of the vine into New South Wales” (London, 1834). What kinds of historical understanding could be useful in “The Business of Wine” and its nonidentical twin, “The Wine Industry”? First, the historical legacies and traditions associated with wine, viticulture and winemaking remain central to the rise of Mediterranean-wide/Black Sea civilizations and Western traditions of thought. Second, Wine Industry practices and traditions as well as innovations grow in the presence, conscious or otherwise, of history, people, geography and the land. Note, “Wine Country” is an affectionate tasting and welcoming badge in The Hunter Valley – at once evoking ideas of locale and produce. Third, the contemporary histories and practices of viticulture, winegrape growing and winemaking need to harness the histories – social, economic and cultural/geographic of wine in society and culture through time. Markets and ideas of market-trading are as venerable as the ancient Mediterranean and certainly prefigure the pathfinding work of Adam Smith (as Smith himself was aware), and yet the dynamics and locale of markets remain both elusive and challenging. Wine is certainly a beverage but it is much more: wine accompanies histories, cultures and traditions, and it is a possessive and exchangeable commodity. Wine is a cultural food taken through history and over time. 2013-03-26T06:37:20.411Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8769 ℓ⁰ Norm based signal recovery is attractive in compressed sensing as it can facilitate exact recovery of sparse signal with very high probability. Unfortunately, direct ℓ⁰ norm minimization problem is NP-hard. This paper describes an approximate ℓ⁰ norm algorithm for sparse representation which preserves most of the advantages of ℓ⁰ norm. The algorithm shows attractive convergence properties, and provides remarkable performance improvement in noisy environment compared to other popular algorithms. The sparse representation algorithm presented is capable of very fast signal recovery, thereby reducing retrieval latency when handling high dimensional signal. 2013-03-26T06:04:07.260Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8761 Distributed Video Coding (DVC) is a new paradigm for video compression, which is particularly attractive due to its flexibility to introduce very simple encoder structure. However, most DVC systems are unable to adapt to the bandwidth variations. In this paper we propose a scalable DVC scheme, which can adjust the bit-rate linearly depending on the available bandwidth, and thereby achieves optimal quality of service (QoS). Our algorithm combines compressed sensing with multiple measurement vectors problem to achieve significantly low encoding complexity. The correlation structure in the successive video frames is exploited by joint sparsity, which in turn helps reduce decoding complexity. The simulation results depict a significantly improved performance over other low complexity video codec schemes. 2013-03-26T06:03:03.514Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8762 Multiple description coding (MDC) offers an elegant approach to data transmission over lossy packet-based networks. This paper proposes an MDC decoder for Compressed Sensing (CS) based MDC. Our decoder minimizes ℓ⁰ norm of the total variation of the image in a recursive manner, making it effective when different descriptions experience different time delays in the network. The proposed approach brings in a significant performance improvement in reconstruction accuracy and reconstruction time. 2013-03-26T06:02:02.055Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7925 We address the problem of finding a set of sparse signals that have nonzero coefficients in the same locations from a set of their compressed measurements. A mixed lscr₂,₀ norm optimization approach is considered. A cost function appropriate to the joint-sparse problem is developed, and an algorithm is derived. Compared to other convex relaxation based techniques, the results obtained by the proposed method show a clear improvement in both noiseless and noisy environments. 2013-03-26T05:46:21.385Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8894 Every country in the world has some form of an educational system leading to a Vocational Education and Training system. Vocational training is normally post secondary education but in some countries it is initiated during the schooling years. Other developed countries such as the United Kingdom have similarities in their competency based education system to that of Australia. The challenges facing vocational education and training in the United States of America from the mid to the late 1990's had parallel's with those changes occurring in New Zealand at that time, these challenges are now being confronted by the Australian Vocational Education System. Technical Education in New South Wales (NSW) evolved from the privately funded Sydney Mechanic's School of Arts in 1833. The NSW State Government assumed control of this institution in 1883 resulting in the expansion of the Technical Education at a rapid rate, and has developed into what is now called a Vocational Education and Training (VET) system. This comparative study of the MF&W trade course in 2001 and the newly introduced MF&W trade courses in 2004, focuses on the data from the exit tests. The discussions and recommendations also focus on types of benefits or deficiencies this major change has had in the knowledge base of the current apprentices from the trade course. From 1972 to 1990 the MF&W trade course had not changed a great deal in its delivery mode or subject matter. The introduction of the Competency Based Training (CBT) format into the MF&W area of training in 1991 changed it from a lock step method of delivery. Lock step method underpinned the knowledge of the task step by step form whereas the modular based delivery contains the competency required for the task. During the decade that followed, there have been three major reviews of the MF&W (Heavy) trade, which have impacted on delivery, what is taught and how it is taught. 2013-03-25T23:26:21.760Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8746 Lattice-reduction-aided detection (LRAD) has been shown to considerably increase the performance of linear multiple-input multiple-output (MIMO) detection systems. In previous work, we introduced adaptive lattice reduction as a way to exploit channel correlation to yield lattice reduction-based detectors exhibiting considerably reduced complexity. In this paper, we review adaptive lattice reduction and examine the performance and complexity of this detection scheme in both temporally and frequency fading channels. For typical mobile environments, for example, we demonstrate a complexity reduction approaching 33% on a 4times4 system, without compromising performance. 2013-03-25T01:46:38.263Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8056 In this paper we design practical interleavers for regular, systematic repeat-accumulate (RA) codes. The new interleavers, which we call L-type and modified L-type interleavers, are deterministic, described by a single parameter, and straightforward to implement. Despite their simple description, the new interleavers are shown to perform equally as well as, or better than, traditional interleavers over a wide range of code lengths and rates. 2013-03-25T01:41:22.207Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8734 We consider arbitrarily many interconnected integral Input-to-State Stable (iISS) systems in an arbitrary interconnection topology and provide an (i)ISS comparison principle for networks. We show that global asymptotic stability of the origin (GAS) of a lower-dimensional system termed the comparison system, which is based on the individual dissipative Lyapunov iISS inequalities, together with a scaling condition implies the existence of an iISS Lyapunov function of the composite system. A sufficient (but not necessary) condition for 0-GAS of the interconnection is shown in this paper to be the generalized small-gain condition derived by Dashkovskiy et al., but this time in a dissipative Lyapunov setting. We also provide geometric intuition behind growth rate conditions for the stability of cascaded iISS systems. 2013-03-25T01:32:57.674Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9160 This paper studies LTI one-degree-of-freedom networked control architectures built around LTI SISO plants. The feedback path comprises an unreliable channel that drops data in an i.i.d. fashion. We extend known results to show that there exists a second order moments equivalence between the situation examined and an auxiliary feedback loop where the unreliable channel has been replaced by an additive i.i.d. noise channel that has an equality signal-to-noise ratio constraint. We then use these insights to design optimal controllers. We also establish a necessary and sufficient condition on the successful transmission probability that allows for the design of a controller that guarantees MSS in the considered setup. Our proposal does not require packet arrival acknowledgements. Thus, our results give necessary and sufficient conditions for MSS in an output-feedback control architecture with UDP-like protocols. 2013-03-24T05:18:59.589Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8723 We study a control architecture for linear time-invariant plants which are affected by random disturbances. The distinguishing aspect of the situation at hand is that an unreliable data-rate limited network is placed between controller and the plant input. To achieve robustness with respect to i.i.d. dropouts, the controller transmits data packets containing quantized plant input predictions. These minimize a finite horizon cost function and are provided by an appropriate optimal entropy coded dithered lattice vector quantizer. Within this context, we derive an equivalent noise-shaping model of the closed loop system. This model is employed for the design and analysis of the vector quantizer used by the controller. 2013-03-24T05:18:01.585Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8780 We study a state estimation architecture for sensor networks, where several sensors transmit quantized innovations to a central estimator. Transmission is via a wireless channel, which is prone to fading leading to random packet loss. State estimation is carried out at the gateway via a time-varying Kalman filter which accounts for packet loss and quantization effects. To form the innovations at the sensors, the estimator transmits information regarding its current state estimate to the sensors. This information could be dedicated to each sensor or broadcast to all sensors. In addition, the gateway also decides upon power levels and quantization step-sizes to be used by each sensor node. Here, we adopt elements of predictive control to trade off estimation performance versus energy use. 2013-03-24T05:17:29.033Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8715 In this work, we construct a novel scheme for efficient perceptual coding of audio for robust communication between encoders and wireless hearing aids. To limit the physical size of the hearing aids and to reduce power consumption and thereby increase the lifetime expectancy of the batteries, the hearing aids are constrained to be of low complexity. We therefore provide an asymmetric strategy where most of the computational load is placed at the encoding side. We make use of multiple-description coding. This combats possible erasures on the wireless link between the encoder and the hearing aids without introducing significant delay. Furthermore, we employ psychoacoustically optimized noise-shaping quantizers based on the moving-horizon principle, which exploits a finite prediction horizon. 2013-03-24T05:17:01.074Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8716 We study state estimation via wireless sensor networks over fading channels affected by random packet loss. In the configuration examined, the sensors send their measurements to a single gateway, which decides upon the source coding scheme and the sensor transmitter power levels. The decision process is carried out on-line and adapts to changing channel conditions to achieve an optimal trade-off between estimation quality and sensor energy expenditure. In particular, if some channel conditions are poor, then the gateway commands the corresponding sensors to increase power levels and use multiple-description coding. Simulations based on measured channel data illustrate that the proposed scheme gives excellent results. 2013-03-24T05:16:23.126Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8765 Finite Control Set Model Predictive Control (FCS-MPC) is a novel and promising control scheme for power converters and drives. Many practical and theoretical issues have been presented in the literature, showing good performance of this technique. The present work deals with one of the most relevant aspects of any controller, namely, the steady-state operation. As will be shown, basic FCS-MPC formulations can be enhanced to achieve a zero average steady-state error. We focus on a simple H-Bridge power converter with two complementary switches and discuss benefits and drawbacks of our proposal. 2013-03-24T05:15:22.297Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8751 This paper presents a predictive strategy for the control of a permanent magnet synchronous motor (PMSM). Our approach allows one to simultaneously manipulate speed and electrical variables, without using any auxiliary linear controller. The high sampling rate, characteristic of this technique, and the limited precision of the typical angle measurement devices, present serious difficulties for this technique to work in practice. These issues are dealt with in the paper and a solution based on an extended Kalman filter is proposed. The effectiveness of the proposed approach is evaluated through simulations. 2013-03-24T05:14:42.808Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8735 This paper presents the use of a predictive technique to control the currents in a PMSM, driven by a voltage source inverter. This method allows for a high quality current control without using linear controllers and modulators, resulting in a conceptually simple solution. Simulation an experimental results confirm the good performance of the drive controlled by this method. 2013-03-24T05:14:05.900Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9161 Multilevel Converters (MCs) have emerged as a promising alternative to traditional two level converters. These topologies present a better output voltage quality due to the reduction of the voltage steps by increasing the voltage number levels. Within the MC family, flying capacitor converters present a special attraction due to the easy way to increase output voltage levels by adding cells. Recently model predictive control algorithms have reached a special interest in MCs applications. In particular, finite control set predictive control algorithms applied to flying capacitor converters have shown that it is possible to achieve a good performance in the control of capacitor voltages and output current. For that purpose, at each sample time the controller explores all the switching states and determines the optimal one to be applied. However, the number of switching states grow exponentially in relation to the number of cells. This increases the time that the algorithm takes to find the optimal switching state. In this paper we present an off-line strategy to reduce the number of switching states to be explored in a finite control set predictive algorithm by using only those which produce that the system state point towards to the reference. Moreover, a sampling period design is presented to guarantee that the system state remains inside of a positive invariant set. 2013-03-24T05:13:07.976Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8678 Multilevel converters have emerged as a promising alternative to traditional two level converters, especially flying capacitor converters because of the fact that this topology requires only a main DC-link voltage and presents a easy way to increase the output voltage levels by increasing the number of cells. Unfortunately, a balancing of capacitor voltage is required. Recently, predictive control algorithms have been presented in order to control not only the output current but also to achieve good performance in the balancing of the capacitor voltages. For this purpose, it is necessary to know the state of these voltages generally taking a measurement of them, therefore the number of sensors required will be increased regarding the output voltage levels desired. This paper presents an estimation of the capacitor voltages using a discrete Kalman filter. This algorithm is employed to determinate correctly the system state and thus provides this information to the predictive controller in order to determinate the best switching combination to be applied in the next sample period. 2013-03-24T05:12:16.347Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7772 It is widely accepted that transdisciplinary approaches to environmental problem solving provide the best hope for humans to address the issues associated with climate change. The education of professionals in the design and construction/manufacturing sectors should ideally sensitise students to these principles, helping them to recognise the value that other professions bring to the design process, and consequently minimise the environmental impact of their designs. A course on “design and the environment” delivered at the University of Newcastle in Australia embraces these principles, delivering content to mixed cohorts that include design and technology teachers, industrial designers, architects, engineers, and construction managers. It is founded upon problem based learning principles, empowering the students to take ownership of their learning. This extends to the consequences of their designs as they are required to perform a life cycle analysis for their product/building, encouraging them to explore the vexing issues of environmental auditing. Previous evaluation of the course has qualitatively indicated its effectiveness in raising the students’ environmental awareness, and this paper confirms this using pre- and post-intervention content analysis of students’ documents to measure the effect. The analysis utilises a framework based on the New Ecological Paradigm, and yields interesting results. The paper concludes with a discussion of the implications for course design and the responsibility of the educator in global society. 2013-03-22T04:46:01.399Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8856 Qantas is an international airline operating in a turbulent environment with cost, infrastructure and demand pressures forcing a major consolidation of the industry. With a national industrial relations climate which could be labelled as generally 'benign' for employers over the last decade Qantas has had a series of disputes with its unions over recent years. This has been noteworthy in the context of very low levels of industrial disputation. As an integrated and international airline Qantas has a number of strategies available to it to reduce costs and marginalise unions. Drawing on the literature of the industrial relations policies of multinational corporations, the paper considers the options and constraints facing Qantas as further turbulence hits the airline industry. 2013-03-20T05:07:42.463Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9091 In this paper we investigate whether socially responsible investment - investment seeking both financial and social returns - influences the management of employment relations within corporations. Many SRI funds use investment criteria that expressly incorporate employment relations indicia; meaning that they either look to invest in companies with good reputations for employment relations or exclude companies with poor workplace practices. A further and increasingly popular approach is to try to influence corporate policy on issues of importance to the SRI fund through engagement. Given these objectives, it is relevant to ask whether SRI actually does influence employment relations and to what degree? Drawing on an analysis of SRI funds criteria and interviews with Australian SRI funds managers and consultants, we argue that although SRI has the potential to influence the management of employment relations it has not yet reached the stage of exercising significant influence. 2013-03-20T05:06:20.744Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9106 This paper explores the literature relating to the employment relations practices of multinational companies (MNCs) operating in Australia and Australian MNCs operating overseas. These practices are framed in the context of theoretical debates concerning the apparent emergence of ‘multicentred’ or ‘heterarchic’ organisational forms in MNCs, the ‘country of origin’ effect that arises from the embeddedness of MNCs in the institutions of the home country and the extent to which there is a ‘corporate division of labour’ which governs the character of work in MNCs. 2013-03-20T05:01:24.149Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8808 This paper reviews the literature on employment relations in MNCs in Australia. It finds that first the central local debate is prominent both in relation to foreign MNCs in Australia and Australian MNCs overseas. Second, there are many factors influencing central local control. These include; country of origin effect, type of product and product market; firm size, company and HR structure, language and cultural proximity and geographical distance. Third, host country effects are prominent in terms of structural and institutional change, many companies and industries appear to have taken advantage of more favourable conditions to reshape their workforces. 2013-03-20T04:59:55.279Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8774 The article reflects upon the recent experience of one multinational in the aerospace sector: Boeing, a global manufacturer based in the USA. For the past decade the level of industrial disputation in Australia has been relatively low, so it is noticeable when there are major IR disputes at separate workplaces of the one MNC. Given the considerable shifts in the industrial relations environment in Australia, there is the opportunity to examine how MNCs adapt to the new environment. In the two case study organisations we can observe that both organisations have developed an aggressive stance towards employees and unions and both organisations are prepared to utilise the new IR legislation. Boeing, as an MNC has a range of options available to improve its IR conditions (eg outsourcing, relocating production), however there are limits imposed by servicing and contractual agreements, particularly procurement arrangements with governments. Boeing’s plants in Australia have quite different IR traditions, reflecting whether there is a Greenfield or an existing site. In both cases there is a pragmatic and reactive strategy implemented that in part is governed by the prevailing economic environment and by the choices offered by the national industrial relations system. The article is organised as follows. There is a discussion of multinationals and industrial relations. Then there follows a brief review of previous studies of MNCs and IR in Australia. Following this the changes to the industrial relations system are outlined. The two case studies within Boeing are then discussed. Finally, the article concludes with a discussion regarding the choices and decisions made by MNCs in the context of a shifting national IR landscape. 2013-03-20T04:58:35.740Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9094 The extent of industrial democracy in Australia is limited, with generally few formal mechanisms for employee participation and voice in the governance and management of organisations despite the normative claims of the human resource management movement. Along with low levels of union density, the Workchoices legislation clearly set out to reduce representation and participation even further by attempting to facilitate the exclusion of unions from the workplace. However, we see some scope for extending industrial democracy and implicitly trade union presence through the lever of industry superannuation funds. An initial study of the investment practices of industry superannuation funds identified few actively pursue socially responsible investment. We contend, therefore, industry funds, within their obligations imposed under the relevant superannuation law, to promote labour standards and improved industrial relations practices. 2013-03-20T04:56:33.883Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8896 In the context of an increasingly tight labour market, the issue of not only attracting but, more importantly, retaining staff is becoming more pronounced. These issues have been well publicised in such sectors as health and mining, where the skills shortage has been instrumental in attracting skilled migrants. However, hospitality is one sector that has experienced voluntary, high labour turnover for quite some time. Many jobs are short term, unskilled and contingent, so turnover is to be expected. However, in the 4/5 star hotel sector, dominated by multinational corporations, there have been concerns raised within the industry around staff recruitment and staff retention. Previous studies (Knox & Walsh 2005; Timo & Davidson 2005) have highlighted a paradox that appears to be evident, while the industry makes such claims, labour use strategies are generally centred on cost minimisation and labour flexibility strategies that in themselves are not inimical to staff retention. Drawing from information generated by industry reports, Australian Bureau of Statistics (ABS) data and workplace agreements in the hotel sector, this paper provides a closer look at the reasons for staff turnover within the industry and whether the concerns about staff retention are matched by the workplace agreements. The paper presents a preliminary investigation into the strategies (or not) that the larger industry players are employing to facilitate staff retention. 2013-03-20T04:52:05.108Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9146 As businesses restructure their operations the number of call centres is growing through ICT developments. Indeed the ACTU (2002) have argued that call centres are well placed to represent an e-commerce gateway for many companies. The scale, nature, organization and operation of call centres is extremely diverse (Burgess and Connell, 2004) although they share the ability to be organized on a continuous operational basis, they are highly dependent upon ICT platforms and call centre work is capable of being subject to extensive control and surveillance. While research has generated many bleak stories of the work experience in call centres with reference to 20th century workhouses (Callaghan and Thompson, 2001), there are also examples of high levels of job satisfaction combined with job commitment (Kinnie et al, 2001). Kjellerup (2004) has referred to two types of call centre as being either ‘The Galley Slave Model’ or the ‘Coaching Culture Model’. We propose it is time to search for a new management model for call centres that is not at one or other end of the continuum but perhaps somewhere in the middle. For this paper the authors have focused on work in the context of two small-medium sized call centres – with between 50 and 150 seats. This is because much of the research to date has focused on large call centres, with several hundred operatives. As a result in our search for a different management model we intend to look beyond the most commonly examined locations. The purpose of the paper is to first outline the nature and dimensions of the call centre industry in Australia before analysing the drivers of organizational and workplace change in the industry. Next, we consider the substantive job quality issues that surround call centre work. The paper then considers the findings from structured focus groups with operatives and team leaders in the featured Australian call centres in order to determine how the role of management may impact on employee’s perceptions of job quality, commitment and fairness given the drive to increase productivity in the current economic climate. We conclude by proposing a typology for call centre management. 2013-03-20T04:49:57.573Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9107 Minimum wages remain a feature of advanced economies. Even in countries with neo-liberal policy settings, the minimum wage remains. Why, in a neo-liberal context, are minimum wages retained? To consider these issues we examine Australia, the UK and the USA. We also examine the processes associated with minimum wage adjustment including coverage, enforcement, frequency, determination criteria and timing. On these issues we demonstrate some major differences across the minimum wage systems. 2013-03-18T06:04:49.238Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8773 We outline the key features of the Hunter Valley Wine cluster through reviewing its history and development; outlining its organisational features and reflecting on the abiding and unique characteristics of the cluster are. We then turn to prior review and analyses of the Hunter Valley Wine cluster in order to highlight the key features from these studies. Following we then include an analysis of prior studies of wine clusters in order to highlight information flows in the Hunter Valley Wine Cluster. The article serves as a background to the understanding and evaluation of the Hunter Valley Wine Cluster. 2013-03-18T06:02:43.232Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9013 This paper investigates the role of institutional thickness in inter-organisational collaboration in clustered firms. Institutional thickness refers to an integrated and interlocking web of supporting formal and informal institutions including local chambers of commerce and trade associations as examples of the former, and social networks as examples of the latter (Keeble et al 1999). We theoretically explore the extent to which, and mechanisms through which, institutional thickness facilitates collaboration, drawing on concepts of reciprocal altruism, transactive memory and institutional proximity. We argue that institutional thickness fosters a cluster-wide climate of trust and a context conducive to reciprocal altruism (Trivers 1971), which reduces the threat of opportunism and stimulates collaboration towards shared valued outcomes. We further propose that institutional thickness facilitates the development of a shared understanding of sources of valued resources, as well as the adoption of shared values, approaches and policies, which minimise misunderstanding and normative barriers to collaboration. This review makes a number of important contributions to the field. First, we respond to the recognition that much of the research interest in collaborative interaction in clusters has been focused on its description and categorisation, and there have been recent calls for a movement away from ontological investigations to an explanation of the underpinning causes and assumptions (Knoben & Oerlermans 2006). In investigating the factors underpinning the mechanisms through which institutional factors support collaboration, we directly respond to criticisms that much extant literature gives no attention to the factors that differentiate between high-performing and unsuccessful clusters, and begin to address the research gap surrounding the complex, but highly important, micro-level interactions that explain cluster effects on firm dynamics and performance (Cooper & Park, 2008). Second, we highlight how institutional thickness can contribute to value adding activity at the level of the individual firm and in the context of the cluster as suggested in the model of an industry cluster as a value adding web (Brown et al, 2007). We then refer to the Hunter Wine cluster to illustrate the outlined analysis. 2013-03-18T06:00:44.243Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6958 Considerable changes in the workforce and in industrial relations legislation have resulted in gaps in the system of representation and industrial relations regulation in Australia. With a falling trade union density the issue of employee voice outside of trade unions is addressed in this paper. The literature on industrial relations “actors” is reviewed and the discussion turns to contemporary developments in the Australian industrial relations system and the emergence of “new” actors. 2013-03-18T05:55:31.604Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8229 This article assesses the 'Managing Diversity' (MD) approach in Australia, examining its drivers, discussing its relationship to legislation designed to promote equity, and examining it as a set of management practices. It has been plausibly argued, on efficiency grounds, that responsibility for achieving equality objectives must be shifted to organisations as this links contextual conditions to organisational processes. However, even where there is some prescription and guidance such as that provided by Australian Equal Employment Opportunity (EEO) legislation targeted specifically to women employees, both practice and outcomes are variable. This is even more the case with MD where there are no guiding principles or legislative support. The article examines the best practice EEO and MD programs of Australian organisations to demonstrate the approaches and programs that are being developed at the workplace and to highlight the limitations of the 'business case' approach underlying such programs. 2013-03-18T05:54:01.233Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9110 Dubai has evolved from a sparsely populated desert region on the Arabian Gulf to a dynamic and fast growing city. The boom in construction and services is built upon a large immigrant labour force. The labour market is highly segregated firstly between local and expatriate workers, and secondly among the expatriate workers depending on whether they are categorised as professional, construction or service sector workers. Despite the rapid growth and manifestations of modernity in Dubai there are stories emerging concerning the violation of human rights particularly with respect to contracted migrant workers. Despite its rapid transformation Dubai does not have the institutions or infrastructure that support and protect fundamental labour standards and even where there are regulated migrant programs (as in Dubai), workers are potentially subject to exploitation. This paper examines the labour market and industrial relations system in Dubai and asks whether growth is compromised by promoting fundamental labour standards. 2013-03-18T05:52:16.526Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8710 Half duplex devices are widely used in today's wireless networks. These devices can only send or receive, but not do both at the same time. In this paper, we use cooperative decode-forward relay strategies to increase the throughput of half-duplex wireless networks. Due to the half duplex constraint, relays need to carefully choose their transmission states in order to maximize the throughput. We show that the transmission schedule optimization can be formulated as a linear programming problem. Although the number of possible states grows exponentially as the number of relays increases, only a small subset of these states needs to be used in the optimal transmission schedule. This observation allows us to use heuristic algorithms to solve for near-optimal schedule in large networks. Our numerical results show that the decode-forward strategy can provide nearly 3 times more throughput than the traditional multi-hop relaying strategy in half duplex wireless networks. 2013-03-18T04:07:23.571Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8872 Governance of economic exchange or transactions is at the core of the growth and development of the economy. Sharing similar intellectual heritages, transaction cost economics (TCE) and new institutional economics (NIE) both seek to understand how exchange is conducted. 2013-03-18T00:27:50.849Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:4651 We study a source coding method for Networked Control Systems (NCS’s) for SISO LTI plant models. To make efficient use of limited communication resources between controller and plant actuator, we develop a non-uniformly sampled subband coding NCS architecture which we design to minimize a bound on the tracking error variance caused by quantization effects. Our main contribution, in relation to earlier work on subband coding NCS’s, lies in that we allow each subband to be equipped with pre- and post-filters. To characterize optimal filters and to solve the subband bit-allocation problem, we model quantization effects via signal-to-noise ratio constraints and explicitly take into account the closed loop nature of signals. Simulation results verify that the resultant designs perform exceptionally well, even in non-idealized situations. 2013-03-17T23:29:42.907Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6758 This paper describes a novel approach to quantization in oversampled filter banks. The new technique is based on moving horizon optimization, does not rely on an additive white noise quantization model and allows stability to be explicitly enforced in the associated nonlinear feedback loop. Moreover, the quantization structure proposed here includes ΣΔ and linear predictive subband quantizers as a special case and, in general, outperforms them. 2013-03-17T23:29:07.012Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:6757 Multilevel converters and, in particular, flying capacitor (FC) converters are an attractive alternative for medium-voltage applications. FC converters do not need complex transformers to obtain the DC-link voltage and also present good robustness properties, when operating under internal fault conditions. Unfortunately, with standard modulation strategies, to increase the number of output voltage levels of FC converters, it is necessary to increase the number of cells and, hence, the number of capacitors and switches. In this paper, we develop a finite-state model predictive control strategy for FC converters. Our method controls output currents and voltages and also the FC voltage ratios. This allows one to increase the number of output voltage levels, even at high power factor load conditions and without having to increase the number of capacitors and switches. Experimental results illustrate that the proposed algorithm is capable of achieving good performance, despite possible parameter mismatch. 2013-03-17T23:28:34.727Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8689 This paper reports the modeling, fabrication and characterization of a SOI-based electro-mechanical transducer used for energy harvesting. The electrostatic transducer couples the ultrasonic energy with the vibration of a seismic mass, converting ultrasonic mechanical energy into electrical energy by means of polarized movable capacitor with comb structures. To extract ambient kinetic energy with arbitrary motion directions, this paper introduces a novel 2D resonator with resonance frequencies of 38520 Hz and 38725 Hz. Working in diagonal direction, the -10 dB bandwidth is 302 Hz, twice wider than 1D resonator devices. The measured dynamic frequency response shows that a maximum peak-to-peak output voltage of 10 mV can be obtained through a 1 M ohm resistive load, and the harvested power is calculated as 0.1 nW. Potential applications for powering battery-free implanted biomedical devices are also discussed in this paper. 2013-03-15T03:40:36.448Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8694 Piezoelectric tube scanners are widely used in nanopositioning applications such as in scanning probe microscopy. Capacitive or inductive sensors are used to provide feedback to improve bandwidth and accuracy of these tube scanners. However, these sensors contain certain noise densities which restrict the bandwidth of the closed loop system if nanometer resolution is required. The use of piezoelectric strain-induced voltage as a measurement signal has been recently proposed to provide feedback with a noise profile of up to three orders of magnitude better than capacitive sensors. This technique uses a quadrant of the electrode for actuation and the opposite quadrant for sensing. The major drawbacks of this arrangement are that the travel range of the tube is reduced by half and the tube is not driven symmetrically; thus the tube is not a collocated system. In this article, a novel electrode pattern of a tube scanner which addresses the above issues and allows for simultaneous actuation and sensing is presented. By using the piezoelectric strain voltage as measurement, an Integral Resonant Control (IRC) method combined with a feedforward inversion technique is implemented to achieve high-speed and accurate scanning performances of the tube. 2013-03-15T02:56:01.572Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8717 In this work, we propose a new control approach for a single-link flexible manipulator, based on the integral resonant control (IRC) scheme. A hybrid control scheme consisting of two nested loops by treating the joint angle and the torque measured at the base of the arm (coupling torque) as the system outputs are formulated. It is shown that the IRC scheme, a high performance controller design methodology for flexible structures with collocated actuator-sensor pairs, can be implemented in a flexible manipulator to achieve precise end-point positioning with effective vibration suppression. Experimental results are presented in order to validate the proposed control scheme. Finally, a brief discussion is included to highlight the contributions of this work in broad area of controlling single-link flexible manipulators. 2013-03-15T02:54:17.988Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8748 The atomic force microscope (AFM) is a device capable of generating topographic images of sample surfaces with extremely high resolutions down to the atomic level. It is also being used in applications that involve manipulation of matter at a nanoscale. Early AFMs were operated in open loop. As a result, they were susceptible to piezoelectric creep, thermal drift, hysteresis nonlinearity and scan-induced vibration. These effects tend to distort the generated image. The distortions are often minimized by limiting the scanning speed and range of the AFMs. Recently a new generation of AFMs has emerged that utilizes position sensors to measure displacements of the scanner in three dimensions. These AFMs are equipped with feedback loops that work to minimize the adverse effects of hysteresis, piezoelectric creep and thermal drift on the obtained image using standard PI controllers. These feedback controllers are often not designed to deal with the highly resonant nature of an AFM's scanner, nor with the cross-coupling between various axes. In this paper we illustrate the drastic improvement in accuracy and imaging speed that can be obtained by proper design of a feedback controller. Such controllers can be incorporated into most modern AFMs with minimal effort since they can be implemented in software with the existing hardware. 2013-03-15T02:45:12.283Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8696 Most commercially available Atomic Force Microscopes (AFMs) use piezoelectric tube nano-positioners for scanning. Current scanning frequencies are less than 0.01fr, where fr is the frequency of the first resonant mode of the piezoelectric tube used. An improvement in the scanning rates without losing the nano-scale precision is desired. Here, a prototype of the scanning unit of an AFM is considered. The dynamics of the piezo tube, used in the prototype, is approximated by a model that satisfies the negative imaginary property. The resonant mode that hampers the fast scanning is identified from the model and damped using a feedback control technique known as the Integral Resonant Control (IRC). The piezoelectric tube is then actuated to have fast and accurate scans. 2013-03-15T02:43:38.455Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8674 Piezoelectric-stack actuated platforms are utilized in many nanopositioning applications. Their performance is limited by their low-frequency resonance due to the mechanical construction as well as piezoelectric nonlinear effects. We propose a hybrid control scheme comprising a loop-shaping H∞ controller and an inversion-based feedforward control scheme, capable of delivering accurate nanopositioning performance at relatively high speeds, upto 40 Hz. It is shown that the implemented control strategy is robust in the presence of uncertainty in resonance frequency due to loading. It is also shown that by employing charge actuation on the fast axis and integral tracking control on the slow axis, accurate raster scans can be obtained. Experimental results that show resonance damping, integral tracking action as well as the robustness of the implemented control scheme to resonance frequency uncertainty are presented. Finally, raster scans recorded at 10 Hz, 20 Hz and 40 Hz are presented to show the achievable positioning performance. 2013-03-15T02:41:43.499Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9016 This paper forwards the proposition that, explaining the contrasting approaches of ‘Old’ and ‘New World’ wine producers in the context of formal institutional differences (e.g. regulation), with cursory reference to cultural differences from which such institutions are, in part, derived, may limit our understanding of underlying differences that exist between’ Old’ and ‘New World’ producers. A bottom-up approach to analysis is proposed, starting with an understanding of the human values systems (Schwartz, 1992) of individuals working or producing in the industry. This paper argues that differences in human values between ‘Old’ and ‘New World’ producers may better explain the sources and consequences of the contrasting ‘rules of the game’ (North, 1990) experienced across the global wine industry. We also propose that commonalities in values should be understood at a regional level, as regional ‘industry bounds’ (Peng, 2006) are the most fitting form of industry demarcation. 2013-03-14T23:45:47.220Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:8740 In this paper, nonlinear model predictive control is applied to an inverted pendulum apparatus. The sample interval for control calculations is 25 milli-seconds and the associated non-convex constrained optimisation problem involves 61-variables with 241-constraints. Despite this being a challenging problem, it was solved online using a standard sequential quadratic programming approach on a modest hardware platform. The efficacy of the control algorithm is validated via experimental results. 2013-03-14T05:34:18.178Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9166 This paper considers the system architecture and design issues for implementation of on-line Model Predictive Control (MPC) in Field Programmable Gate Arrays (FPGAs) and Application Specific Integrated Circuits (ASICs). In particular, the computationally itensive tasks of fast matrix QR factorisation, and subsequent sequential quadratic programming, are addressed for control law computation. An important aspect of this work is the study of appropriate data word-lengths for various essential stages of the overall solution strategy. 2013-03-14T05:30:41.035Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:7947 This paper addresses the problem of estimating linear time invariant models from observed frequency domain data. Here an emphasis is placed on deriving numerically robust and efficient methods that can reliably deal with high order models over wide bandwidths. This involves a novel application of the expectation-maximization algorithm in order to find maximum likelihood estimates of state space structures. An empirical study using both simulated and real measurement data is presented to illustrate the efficacy of the solutions derived here. 2013-03-14T05:16:51.212Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9061 Microbial induced corrosion (MIC) of reinforced concrete sewers and manholes is a significant problem in sewage systems with global repair costs estimated to be in the order of billions of dollars per year. When the corrosion is sufficiently advanced it can lead to structural failures with potentially serious longer-term operational consequences. While the fundamentals involved in concrete sewer deterioration are reasonably well-understood, the prediction of the rate of deterioration and the quantitative effects of various influencing factors are not well developed. This paper outlines the basic mechanisms involved in deterioration of concrete sewers and the likely effects of various influencing factors, based on currently available information. A brief description of the current knowledge gaps is also provided. A new ARC and industry funded research project is discussed that combines industry and multi-disciplinary university research with the aim of determining the relationship between sewer environmental parameters such as H₂S level, temperature and humidity and the instantaneous corrosion rate of concrete using in situ field observations and extensive laboratory testing. Investigations into the molecular, chemical and material dynamics of the corrosion process will enable an accurate picture of the various underlying processes to be constructed. This data along with historical records and the experience of the industry participants will enable a phenomenological model of the corrosion process to be constructed. It will enable industry to estimate the reliability and the expected remaining physical life of concrete sewers. 2013-03-14T04:42:51.111Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9067 In 2002, the 45 year old Sorell Causeway Bridge in Tasmania’s south east was demolished due to fears surrounding the serviceability of the prestressed concrete beams, in relation to the corrosion of the post-tensioning strands. Attempts were made to determine the extent and severity of the corrosion prior to its demolition by employing a number of conventional non-destructive and diagnostic techniques, yet a firm conclusion could not be reached regarding the structure’s condition. To further investigate the degree of correlation between these conventional assessment techniques and the physical condition of the embedded steel in relation to corrosion risk guidelines recommended in the literature, a number of beams of varying condition were salvaged from the bridge demolition and subjected to further detailed investigations. The current paper focuses on the half-cell potential and chloride profile results obtained for two such beams in good and poor condition relating to the reinforcing and prestressing steel condition. In summary, the comparison of results yielded inconsistencies with the literature guidelines. Survey areas showing highly negative potentials and elevated chloride concentrations did not necessarily indicate corrosion activity or severity. In contrast, instances of severe corrosion were found on both reinforcing and prestressing steel where literature guidelines for these tests recommend that the risk of corrosion is low. 2013-03-14T04:12:41.382Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9065 The time before visible evidence appears on the external part of a reinforced concrete structure is often used an indicator of the rate at which the reinforcement is corroding. The conventional wisdom is that this is a function of the rate at which chlorides from the marine environment (or from de-icing salts) reach the reinforcement. Current good practice requires high quality concretes with thick and low permeability cover to ensure long initiation times. This has been known for many years. Many modern structures show evidence of corrosion initiation already within 10-20 years. On the other hand, there is recorded evidence that many older reinforced concrete structures exposed to aggressive marine environments have survived for long periods of time with little or no evidence of reinforcement corrosion. In many cases this is despite thin covers and relatively poor quality concretes. This paper gives a summary of many structures recorded in the literature, both for cases with and without early corrosion evidence. It is proposed that understanding the differences in behaviour is the key to understanding longer-term durability of reinforced concrete structures in marine environments. The available evidence to date indicates that concretes with high pH buffering, such as imparted by calcareous aggregates, have considerably greater durability against reinforcement corrosion. Three Australian examples are given. 2013-03-14T04:09:39.250Z ]]>